import java.util.Scanner;

/**
   Determines the average number of characters for words in a string.   
   Input: a string of one or more lines containing words
   Output: the average number of characters per word in the string 
      to two decimal places
*/
public class WordAvg
{
   public static void main(String[] args)
   {
      Scanner in = new Scanner(System.in);

      // your work here
      double average = 0.0;
      double count=0.0,num=0.0; 

      while (in.hasNext())
      {
         String word = in.next();

         // more work here
         int l = word.length();
         for(int i = 0;i<l;i++){
            if(word.charAt(i) == 32)
            count++;
            
         }
         num = l+1.0;


      }
      
      // more work here
      num -= count;
      count +=1.0;
      average = num/count;
      System.out.printf("%.2f\n", average);
   }
}